In the processing and packaging of semiconductor devices, wire bonding continues to be the primary method of providing electrical interconnection between two locations within a package (e.g., between a die pad of a semiconductor die and a lead of a leadframe). More specifically, using a wire bonder (also known as a wire bonding machine) wire loops are formed between respective locations to be electrically interconnected.
An exemplary conventional wire bonding sequence includes: (1) forming a free air ball on an end of a wire extending from a bonding tool; (2) forming a first bond on a die pad of a semiconductor die using the free air ball; (3) extending a length of wire in a desired shape between the die pad and a lead of a leadframe; (4) stitch bonding the wire to the lead of the leadframe; and (5) severing the wire. In forming the bonds between (a) the ends of the wire loop and (b) the bond site (e.g., a die pad, a lead, etc.) varying types of bonding energy may be used including, for example, ultrasonic energy, thermosonic energy, thermocompressive energy, amongst others.
In conventional wire bonding systems, the bonding energy (e.g., ultrasonic energy) is typically applied after some level of contact is established between the wire/bonding tool and the contact to which the bond will be made. If the bonding energy is applied when the contact (e.g., a lead of a leadframe) is not “pinned down” undesirable bonds may be formed. More specifically, vibration and related problems may result in over squashed bonds, short wire tail lengths after second bond, etc.
Thus, it would be desirable to provide improved methods of bonding energy application, bonding force application, and related wire bonding methods.